Scale platform locking mechanism



Dec. 26, 1939. w p, UNRUH ET! AL SCALE PLATFORM LOCKING MECHANISM Filed Jan. '6, 1939 INVENTOR5. Maw/70D. (l/vew/ Ill/60 2. 8554/6 BYIZ 6% Q mATTORNEYfi Patented Dec. 26, 1939 UNITED. sures i ATENT OFFICE 4 Claims. (01. 2c5 72) This invention relates to locking mechanisms, and particularly to locking mechanisms for scale platforms and the like adapted for heavy duty service.

' It is an object of the invention to provide a locking mechanism for scale platforms which is simple in structure, economical to produce, and which will be rugged and effective in operation.

, The invention provides a locking mechanism for scale platforms and the like which may be readily operated from a suitable operating station, for.

I leverage or otherwise disturbing its adjustment.

' Still more particularly, the invention provides means for locking the scale platform without lifting it from its normal points of support. The locking devices can be used with various and different types of scale mechanisms.

Other objects, advantages, and features of the invention will appear from the following specification when taken in connection with the accompanying drawing wherein one preferred embodiment of the invention is illustrated.

In the drawing, wherein like reference numerals refer to like parts throughout:

Fig. 1 is a general assembly view, partly in section of a weighing scale embodying the locking mechanism of the present invention.

Fig. 2 is a partial perspective view of the looking and weighing mechanisms. v

Fig. 3 is a detail of a portion of the locking mechanism, showing ,the locking bracket and cam, and

Fig. 4 is a detail perspective view of the lock-.

ing cam.

The weighing scale illustrated comprises a platform It adapted to receive the load to be weighed, for example an automotive truck or vehicle, diagrammatically shown at H. A series of longitudinally extending I-beams or the like l2, l3, l4, l5 and I6 are secured to the underside of the platform Ill. The platform is supported upon the weighing leverage, as best shown in Fig. 2, by means of the end I-beams l2 and [6. These platform I El.

as in the case of shafts 20 and 2 I.

thereof adapted to rest upon supporting balls l8,

the balls in turn being supported upon extensions i9 formed integrally with a pair of shafts 2E and 2| extending transversely underneath the The shafts 20 and 21 are supported on a series of support columns 22 by means of knife bearings 23 formed on the ends of the shafts.

.A pair of arms 25 and 26 are fixed to the shafts ill and it. These arms extend, inwardly toward each other, and they are provided with laterally extending pins 2? at their inner ends. These pins cooperate with a pair of links 28, which may be flexible chains, carried by a pair of extensions 219 formed integrally with a shaft 3d. This shaft is mounted on support columns 3! by means of knife bearings 32 formed on the end of the shaft, The shaft 3t carries an arm or shaft 35 extending transverseiy to a point underneath the scale house 35. The end of arm 35 is adapted to be secured to the cord or link 31 which connects with the weight standard 38. This weight standard carries the usual scale beam (not shown) connected to the cord ill, the beam being adapted to receive replaceable and adjustable weights in the usual manner.

In operation as a load is placed upon the scale platform ill, the support mechanism ll, I8 and is, by which the end I-beams of the scale platform are supported, tends to rotate shafts '20 and 2 I upon their supports 22 in proportion to the Weight of the load. The rotational forces imparted to shafts 2ll and 2! tend to rotate arms 25 and 26, causing pins 2'! to pull downwardly upon links 28, which in turn tend to rotate the shaft 30 upon its supports 3|. The rotational forces imparted to the shaft 30 are in turn transmitted to the link 3lb y means of the arm 35. The link 37, which is thus pulled downwardly in proportion to the load received upon the platform it, operates the weighing beam mechanism carried by the weight standard 38.

The foregoing weighing mechanism constitutes one suitable form of weighing scale to which the locking mechanism of the present invention may be applied. However, it is to be understood that the particular mechanism above set forth is only for purposes of illustration, and that the locking mechanism of the invention may be applied to various types of installations to which it may be suitable.

The locking mechanism comprises a bracket 40 carried upon the underside of the central longitudinally extending I-beam [4 by means of securing bolts or the like 4 I. The bracket 40 is provided with a central U-shaped aperture 42 having straight walls 43 formed at the lower part thereof. A rotatable locking cam 44 is arranged within the aperture 42 of the bracket, the cam being secured upon a shaft 45 rotatably journaled at one end in a bearing block 41 and at its other end in a gear box 48, The bearing block 41 is mounted upon a support rest 49, and the gear box 48 is carried upon the wall 50 of the scale pit. A beveled gear 5i is secured to the end of the shaft 65. This gear cooperates with a beveled gear 52 secured to a shaft 53 extending upwardly into the scale house 38. The upper end of the shaft 53 carries a suitable wheel or handle 54 by which the shaft may be rotated.

In operation as the wheel or handle 54 is rotated, shaft 45 will be correspondingly rotated by means of the bevel gearing 5|, 52. The rotation of shaft 45 causes the corresponding rotational adjustment of the locking cam 4d within the aperture 42 of the bracket ill. The locking cam is of elliptical form, as best seen in Figs. 3 and the major axis A--A of the cam being equal to the width of the aperture #2, and the minor axis B-B of the cam being somewhat less than the width of the aperture. When the cam is turned into its horizontal position as shown in full lines in Fig. 3, the cam engages the surfaces 4-3 of the bracket securely locking the bracket from longitudinal movement. Inasmuch as the bracket is rigidly secured to the I-beam M, the I-beain and the platform ill will be sirnilarly locked from longitudinal movement. As the cam is rotated into vertical position, as shown in dotted lines in Fig. 3, the bracket will be freed for movement without interference f om the locking mechanism. By reference to 3 it will be seen that when the cam is so disposed in vertical position, it is spaced from the walls of aperture 42 a predetermined distance both horizontally and. vertically, thus permitting free movement of the bracket 48 in all directions as may be required in the operation of the weighing mechanism.

The invention provides a simple and economical locking mechanism which may be readily operated by the control 5 1 from a convenient position within the scale house. The mechanism is rugged and reliable in operation. It effectively locks the scale platform against longitudinal movement as the load is placed upon or removed from the platform, and this locking action is effected without in any way disrupting or otherwise disturbing the normal contacts and relations between the various movable parts of the weighing leverage. In fact, vertical movement of the weighing platform is permitted While the locking mechanism is in locking position. By this means the weight of the load is not carried upon the locking mechanism, as in devices wherein the weighing platform is raised bodily by the locking mechanism from the weighing leverage. On the contrary, the load is always carried by the weighing leverage which is designed to receive it, but at the same time all longitudinal movements of the weighing platform during load application and removal, which are the movements which disrupt the positioning and accuracy of the knife bearings, are eliminated. In view of the fact that the platform is never lifted, the positioning of the knife bearings 23 is not disturbed. The locking mechanism prevents disruption or inaccuracy of the weighing mechanism even when the scale platform is subjected to severe shocks, such as by the dropping of an automotive trailer or the like upon it.

It is obvious that various changes may be made in the specific embodiment of the invention set forth for purposes of illustration without departing from the spirit thereof. Accordingly the invention is not to be limited to the specific embodiment shown and described, but only as indiin the following claims.

The invention is hereby claimed as follows:

1. A weighing scale comprising a load plat form, weighing mechanism operated thereby, means for locking the load platform from movement. said locking means comprising a bracket secured to the load platform and having an aperture with a pair of oppositely disposed vertical surfaces, and an elliptical cam rotatable within said aperture and adapted, on rotation, to engage vertical surfaces whereby to lock the bracket .inst movement in a predetermined direction.

2. A weighing scale comprising a load plat form, weighing mechanism operated thereby, means for locking the load platform from move- "it, said locking means comprising a bracket cured to the load platform and having an aperture with a pair of oppositely disposed vertical ces, an elliptical cam rotatable within said i and adapted, on rotation, to engage said vertical surfaces whereby to lock the bracket movement in a predetermined direction, .tllS for rotatably positioning said cam .prlsng a rotatable shaft to which the cam is cured, a second rotatable shaft, a control memied by said second shaft and gearing means LUI connecting said shafts.

3. A locking mechanism for weighing scales and the like comprising a bracket member adapted to be secured to a portion of the scale to be locked, said bracket member having an aperture therein with a pair of oppositely disparallel surfaces, and a rotatable elliptical 1 arranged within said aperture, the major of the cam being equal to the distance betv' surfaces.

ocking mechanism for weighing scales and like comprising a bracket member adapted to be secured to a portion of the scale to be locked, bracket member having an aptherein with a pair of oppositely disposed parallel surfaces, rotatable elliptical cam arwithin said aperture, the major axis of the cam being equal to the distance between said surfaces, and means for rotating the cam within the aperture comprising a rotatable shaft upon which the cam is secured, second shaft, a control member on said second shaft and gearing connections between said shafts.

WILLIAM D. UNRUH. HUGO F. SEELIG. 

